Method and Apparatus for Assigning Fractional Processing Nodes to Work in a Stream-Oriented Computer System

1. A method of making fractional assignments of processing elements to processing nodes for stream-based applications in a distributed computer system, comprising: determining an amount of processing power to give to each processing element by providing a quantity method to determine processing goals for each processing element for a next epoch, wherein the quantity method receives input from a macro model; determining a list of candidate processing nodes to which each processing element can be assigned; determining, based on a list of acceptable processing nodes, fractions of which processing nodes which will work on each processing element by providing a where method configured to minimize differences between goals output by the quantity method and achieved allocations of resources; updating allocations of the amount of processing power and the fractions to increase overall importance of work in the distributed system; reacting to changes in importance of the work by reallocating the amount of processing power and the fractions; and fixing assignments of the processing elements to the processing nodes.

2. The method as recited in claim 1 , further comprising providing limits on an amount of changes permitted to previous fractional assignments.

3. The method as recited in claim 1 , further comprising grouping the processing elements into components, and allocating the processing power to a component using levels of processing power allocation.

4. The method as recited in claim 3 , further comprising employing pacing constraints that specify, for each level of allocation of processing power to the component, a proportion of the processing power to be allocated to each processing element.

5. A computer program product comprising a computer readable storage medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to execute the steps of claim 1 .

6. An apparatus including at least one processor for making fractional assignments of processing elements to processing nodes in a distributed computer system, comprising: a scheduler configured to schedule work using a micro method configured to fractionally allocate processing elements to processing nodes in the distributed computer system to react to changing importance of the work, wherein the micro method includes: a quantity component configured to determine an amount of processing power to give to each processing element and to determine processing goals for each processing element for a next epoch, wherein the quantity component receives input from a macro model including a list of candidate processing nodes to which each processing element can be assigned; a where component configured to determine fractions of which processing nodes which will work on each processing element and to minimize differences between goals output by the quantity component and achieved allocations of resources based on a list of acceptable processing nodes; and at least one delta model which permits updates and corrections in input data for the quantity and where components and which can react to changes in importance of the work by reallocating the amount of processing power and the fractions.